1Apache::AuthDBI(3) User Contributed Perl Documentation Apache::AuthDBI(3)
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6 Apache::AuthDBI - Authentication and Authorization via Perl's DBI
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9 # Configuration in httpd.conf or startup.pl:
10 PerlModule Apache::AuthDBI
12 # Authentication and Authorization in .htaccess:
14 AuthName DBI
16 AuthType Basic
17 PerlAuthenHandler Apache::AuthDBI::authen
19 PerlAuthzHandler Apache::AuthDBI::authz
20 PerlSetVar Auth_DBI_data_source dbi:driver:dsn
22 PerlSetVar Auth_DBI_username db_username
23 PerlSetVar Auth_DBI_password db_password
24 #DBI->connect($data_source, $username, $password)
25 PerlSetVar Auth_DBI_pwd_table users
27 PerlSetVar Auth_DBI_uid_field username
28 PerlSetVar Auth_DBI_pwd_field password
29 # authentication: SELECT pwd_field FROM pwd_table WHERE uid_field=$user
30 PerlSetVar Auth_DBI_grp_field groupname
31 # authorization: SELECT grp_field FROM pwd_table WHERE uid_field=$user
32 require valid-user
34 require user user_1 user_2 ...
35 require group group_1 group_2 ...
36 The AuthType is limited to Basic. You may use one or more valid require
38 lines. For a single require line with the requirement 'valid-user' or
39 with the requirements 'user user_1 user_2 ...' it is sufficient to use
40 only the authentication handler.
41
43 This module allows authentication and authorization against a database
44 using Perl's DBI. For supported DBI drivers see:
45 http://dbi.perl.org/
47 Authentication:
49 For the given username the password is looked up in the cache. If the
51 cache is not configured or if the user is not found in the cache, or if
52 the given password does not match the cached password, it is requested
53 from the database.
54 If the username does not exist and the authoritative directive is set
56 to 'on', the request is rejected. If the authoritative directive is set
57 to 'off', the control is passed on to next module in line.
58 If the password from the database for the given username is empty and
60 the nopasswd directive is set to 'off', the request is rejected. If the
61 nopasswd directive is set to 'on', any password is accepted.
62 Finally the passwords (multiple passwords per userid are allowed) are
64 retrieved from the database. The result is put into the environment
65 variable REMOTE_PASSWORDS. Then it is compared to the password given.
66 If the encrypted directive is set to 'on', the given password is
67 encrypted using perl's crypt() function before comparison. If the
68 encrypted directive is set to 'off' the plain-text passwords are com‐
69 pared.
70 If this comparison fails the request is rejected, otherwise the request
72 is accepted and the password is put into the environment variable
73 REMOTE_PASSWORD.
74 The SQL-select used for retrieving the passwords is as follows:
76 SELECT pwd_field FROM pwd_table WHERE uid_field = user
78 If a pwd_whereclause exists, it is appended to the SQL-select.
80 This module supports in addition a simple kind of logging mechanism.
82 Whenever the handler is called and a log_string is configured, the
83 log_field will be updated with the log_string. As log_string - depend‐
84 ing upon the database - macros like TODAY can be used.
85 The SQL-select used for the logging mechanism is as follows:
87 UPDATE pwd_table SET log_field = log_string WHERE uid_field = user
89 Authorization:
91 When the authorization handler is called, the authentication has
93 already been done. This means, that the given username/password has
94 been validated.
95 The handler analyzes and processes the requirements line by line. The
97 request is accepted if the first requirement is fulfilled.
98 In case of 'valid-user' the request is accepted.
100 In case of one or more user-names, they are compared with the given
102 user-name until the first match.
103 In case of one or more group-names, all groups of the given username
105 are looked up in the cache. If the cache is not configured or if the
106 user is not found in the cache, or if the requested group does not
107 match the cached group, the groups are requested from the database. A
108 comma separated list of all these groups is put into the environment
109 variable REMOTE_GROUPS. Then these groups are compared with the
110 required groups until the first match.
111 If there is no match and the authoritative directive is set to 'on' the
113 request is rejected.
114 In case the authorization succeeds, the environment variable
116 REMOTE_GROUP is set to the group name, which can be used by user
117 scripts without accessing the database again.
118 The SQL-select used for retrieving the groups is as follows (depending
120 upon the existence of a grp_table):
121 SELECT grp_field FROM pwd_table WHERE uid_field = user
123 SELECT grp_field FROM grp_table WHERE uid_field = user
124 This way the group-information can either be held in the main users ta‐
126 ble, or in an extra table, if there is an m:n relationship between
127 users and groups. From all selected groups a comma-separated list is
128 build, which is compared with the required groups. If you don't like
129 normalized group records you can put such a comma-separated list of
130 groups (no spaces) into the grp_field instead of single groups.
131 If a grp_whereclause exists, it is appended to the SQL-select.
133 Cache:
135 The module maintains an optional cash for all passwords/groups. See the
137 method setCacheTime(n) on how to enable the cache. Every server has
138 it's own cache. Optionally the cache can be put into a shared memory
139 segment, so that it can be shared among all servers. See the CONFIGURA‐
140 TION section on how to enable the usage of shared memory.
141 In order to prevent the cache from growing indefinitely a CleanupHan‐
143 dler can be initialized, which skips through the cache and deletes all
144 outdated entries. This can be done once per request after sending the
145 response, hence without slowing down response time to the client. The
146 minimum time between two successive runs of the CleanupHandler is con‐
147 figurable (see the CONFIGURATION section). The default is 0, which runs
148 the CleanupHandler after every request.
149
151* Auth_DBI_data_source (Authentication and Authorization)
152The data_source value has the syntax 'dbi:driver:dsn'. This parameter is
153passed to the database driver for processing during connect. The data_source
154parameter (as well as the username and the password parameters) may be a tilde
155('~') separated list of several data_sources. All of these triples will be
156used until a successful connect is made. This way several backup-servers can
157be configured. if you want to use the environment variable DBI_DSN instead of
158a data_source, do not specify this parameter at all.
159* Auth_DBI_username (Authentication and Authorization)
161The username argument is passed to the database driver for processing during
162connect. This parameter may be a tilde ('~') separated list. See the
163data_source parameter above for the usage of a list.
164* Auth_DBI_password (Authentication and Authorization)
166The password argument is passed to the database driver for processing during
167connect. This parameter may be a tilde ('~') separated list. See the
168data_source parameter above for the usage of a list.
169* Auth_DBI_pwd_table (Authentication and Authorization)
171Contains at least the fields with the username and the (possibly encrypted)
172password. The username should be unique.
173* Auth_DBI_uid_field (Authentication and Authorization)
175Field name containing the username in the Auth_DBI_pwd_table.
176* Auth_DBI_pwd_field (Authentication only)
178Field name containing the password in the Auth_DBI_pwd_table.
179* Auth_DBI_pwd_whereclause (Authentication only)
181Use this option for specifying more constraints to the SQL-select.
182* Auth_DBI_grp_table (Authorization only)
184Contains at least the fields with the username and the groupname.
185* Auth_DBI_grp_field (Authorization only)
187Field-name containing the groupname in the Auth_DBI_grp_table.
188* Auth_DBI_grp_whereclause (Authorization only)
190Use this option for specifying more constraints to the SQL-select.
191* Auth_DBI_log_field (Authentication only)
193Field name containing the log string in the Auth_DBI_pwd_table.
194* Auth_DBI_log_string (Authentication only)
196String to update the Auth_DBI_log_field in the Auth_DBI_pwd_table. Depending
197upon the database this can be a macro like 'TODAY'.
198* Auth_DBI_authoritative < on / off> (Authentication and Authorization)
200Default is 'on'. When set 'on', there is no fall-through to other authentica‐
201tion methods if the authentication check fails. When this directive is set to
202'off', control is passed on to any other authentication modules. Be sure you
203know what you are doing when you decide to switch it off.
204* Auth_DBI_nopasswd < on / off > (Authentication only)
206Default is 'off'. When set 'on' the password comparison is skipped if the
207password retrieved from the database is empty, i.e. allow any password. This
208is 'off' by default to ensure that an empty Auth_DBI_pwd_field does not allow
209people to log in with a random password. Be sure you know what you are doing
210when you decide to switch it on.
211* Auth_DBI_encrypted < on / off > (Authentication only)
213Default is 'on'. When set to 'on', the password retrieved from the database is
214assumed to be crypted. Hence the incoming password will be crypted before com‐
215parison. When this directive is set to 'off', the comparison is done directly
216with the plain-text entered password.
217* Auth_DBI_encryption_method < sha1hex/md5hex/crypt > (Authentication only)
219Default is blank. When set to one or more encryption method, the password
220retrieved from the database is assumed to be crypted. Hence the incoming pass‐
221word will be crypted before comparison. The method supports falling back so
222specifying 'sha1hex/md5hex' would allow for a site that is upgrading to sha1
223to support both methods. sha1 is the recommended method.
224* Auth_DBI_encryption_salt < password / userid > (Authentication only)
226When crypting the given password AuthDBI uses per default the password
227selected from the database as salt. Setting this parameter to 'userid', the
228module uses the userid as salt.
229* Auth_DBI_uidcasesensitive < on / off > (Authentication and Authorization)
231Default is 'on'. When set 'off', the entered userid is converted to lower
232case. Also the userid in the password select-statement is converted to lower
233case.
234* Auth_DBI_pwdcasesensitive < on / off > (Authentication only)
236Default is 'on'. When set 'off', the entered password is converted to lower
237case.
238* Auth_DBI_placeholder < on / off > (Authentication and Authorization)
240Default is 'off'. When set 'on', the select statement is prepared using a
241placeholder for the username. This may result in improved performance for
242databases supporting this method.
243
245 The module should be loaded upon startup of the Apache daemon. Add the
246 following line to your httpd.conf:
247 PerlModule Apache::AuthDBI
249 A common usage is to load the module in a startup file via the PerlRe‐
251 quire directive. See eg/startup.pl for an example.
252 There are three configurations which are server-specific and which can
254 be done in a startup file:
255 Apache::AuthDBI->setCacheTime(0);
257 This configures the lifetime in seconds for the entries in the cache.
259 Default is 0, which turns off the cache. When set to any value n > 0,
260 the passwords/groups of all users will be cached for at least n sec‐
261 onds. After finishing the request, a special handler skips through the
262 cache and deletes all outdated entries (entries, which are older than
263 the CacheTime).
264 Apache::AuthDBI->setCleanupTime(-1);
266 This configures the minimum time in seconds between two successive runs
268 of the CleanupHandler, which deletes all outdated entries from the
269 cache. The default is -1, which disables the CleanupHandler. Setting
270 the interval to 0 runs the CleanupHandler after every request. For a
271 heavily loaded server this should be set to a value, which reflects a
272 compromise between scanning a large cache possibly containing many out‐
273 dated entries and between running many times the CleanupHandler on a
274 cache containing only few entries.
275 Apache::AuthDBI->setProjID(1);
277 This configures the project ID used to create a semaphore ID for shared
279 memory. It can be set to any integer 1 to 255 or it will default to a
280 value of 1.
281 NOTE: This must be set prior to calling initIPC.
283 If you are running multiple instances of Apache on the same server\
285 (for example, Apache1 and Apache2), you may not want (or be able) to
286 use shared memory between them. In this case, use a different project
287 ID on each server.
288 If you are reading this because you suspect you have a permission issue
290 or a collision with a semaphore, use 'ipcs -s' to list semaphores and
291 look for the Semaphore ID from the apache error log. If found, shut‐
292 down Apache (all of them) and use 'ipcrm sem <semaphore key>' to remove
293 the colliding (and hopefully unused) semaphore.
294 You may also want to remove any orphaned shared memory segments by
296 using 'ipcs -m' and removing the orphans with ipcrm shm <shared memory
297 id>.
298 Apache::AuthDBI->initIPC(50000);
300 This enables the usage of shared memory for the cache. Instead of every
302 server maintaining it's own cache, all servers have access to a common
303 cache. This should minimize the database load considerably for sites
304 running many servers. The number indicates the size of the shared mem‐
305 ory segment in bytes. This size is fixed, there is no dynamic alloca‐
306 tion of more segments. As a rule of thumb multiply the estimated maxi‐
307 mum number of simultaneously cached users by 100 to get a rough esti‐
308 mate of the needed size. Values below 500 will be overwritten with the
309 default 50000.
310 To enable debugging the variable $Apache::AuthDBI::DEBUG must be set.
312 This can either be done in startup.pl or in the user script. Setting
313 the variable to 1, just reports about a cache miss. Setting the vari‐
314 able to 2 enables full debug output.
315
317 MOD_PERL 2.0
318 Apache::DBI version 0.96 and should work under mod_perl 2.0 RC5 and
320 later with httpd 2.0.49 and later.
321 Apache::DBI versions less than 1.00 are NO longer supported. Addition‐
323 ally, mod_perl versions less then 2.0.0 are NO longer supported.
324 MOD_PERL 1.0 Note that this module needs mod_perl-1.08 or higher,
326 apache_1.3.0 or higher and that mod_perl needs to be configured with
327 the appropriate call-back hooks:
328 PERL_AUTHEN=1 PERL_AUTHZ=1 PERL_CLEANUP=1 PERL_STACKED_HANDLERS=1
330 Apache::DBI v0.94 was the last version before dual mod_perl 2.x support
332 was begun. It still recommened that you use the latest version of
333 Apache::DBI because Apache::DBI versions less than 1.00 are NO longer
334 supported.
335
337 In some cases it is more secure not to put the username and the pass‐
338 word in the .htaccess file. The following example shows a solution to
339 this problem:
340 httpd.conf:
342 <Perl>
344 my($uid,$pwd) = My::dbi_pwd_fetch();
345 $Location{'/foo/bar'}->{PerlSetVar} = [
346 [ Auth_DBI_username => $uid ],
347 [ Auth_DBI_password => $pwd ],
348 ];
349 </Perl>
350
352 Apache, mod_perl, DBI
353
355* Apache::AuthDBI by Edmund Mergl; now maintained and supported by the modperl
356mailinglist, subscribe by sending mail to modperl-subscribe@perl.apache.org.
357* mod_perl by Doug MacEachern.
358* DBI by Tim Bunce <dbi-users-subscribe@perl.org>
359
361 The Apache::AuthDBI module is free software; you can redistribute it
362 and/or modify it under the same terms as Perl itself.
363perl v5.8.8 2007-03-23 Apache::AuthDBI(3)